<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      font-size: 50px;
    }
    input {
      vertical-align: middle;
    }
  </style>
</head>
<body>
  <div>
    aaaaaa <input type="text">
  </div>
</body>
</html>